Drilling tool and method for producing port seals

ABSTRACT

The present invention provides a new drilling tool useful in machining hydraulic port seals for fluid power ports. The drilling tool drills the port hole to size in a solid material for the minor thread diameter in combination with forming the port in a single operation. The drilling tool has a tool holder having a rotational axis, a first drilling insert having cutting surfaces on a first side and a mounting surface on a second side, at least one second drilling insert having a predetermined cutting surface portion and a mounting portion which is mounted on the holder at a location from the rotational axis of the holder. The at least one second drilling insert has first and second portions which engage and machine a work piece in a drilling operation to form a spot face and a seal form.

This application is a continuation of U.S. patent application Ser. No.11/306,755 filed Jan. 10, 2006, which is a continuation-in-part of U.S.non-provisional patent application Ser. No. 10/642,056 filed Aug. 15,2003, now U.S. Pat. No. 6,984,094 issued Jan. 10, 2006, which claims thebenefit of U.S. Provisional Patent Application Ser. No. 60/404,091 filedAug. 16, 2002, each of which are hereby incorporated by reference.

TECHNICAL FIELD

The invention is directed to a drilling tool for use in production ofpredetermined hole geometries. More particularly, the invention isdirected to a drilling tool useful in machining hydraulic port seals forfluid power ports.

BACKGROUND OF THE INVENTION

In typical drilling operations, a drilling tool is designed to configurea predetermined hole profile in a machining operation to facilitateparticular applications. It is desired to form a predeterminedconfiguration hole profile without secondary machining operations, andin a quick and efficient manner. The cutting or boring action of adrilling tool may be performed by an elongated, substantiallycylindrical drilling tool, such as a combination of a tool holder and adrill insert attached thereto. Typically the cutting insert engages thematerial to be cut upon relative rotation between the tool and workpiece. The use of cutting inserts allows for quick changing of theinsert upon wear of the cutting surfaces, instead of replacement of theentire tool. Further, the use of cutting inserts allows one tool to beused for varying boring applications by changing the insertconfiguration instead of the entire drilling assembly.

In known port contour cutters for the above application, the tools aretypically made of solid HSS, braised tipped carbide, indexable carbideinserts or replaceable carbide inserts. In known configurations andprior methods of forming port holes have generally required multiplemachining operations. For example, the manufacturer of a port hole hastypically required a first step of spot drilling the port hole,thereafter pre-drilling the port hole and a third operation to size theminor thread diameter and form the port hole. This operation typicallyencompassed the following after pre-drilling: (1) ream and then use aform tool with a pilot for the port form, and (2) ream and port formcombination tool, with the reamer used as a pilot. It would therefore bedesirable to provide a drilling tool and method which will drill theport hole to size in a solid material for the minor thread diameter incombination with forming the port in a single operation. Further, inknown configurations, the tools are radially non-adjustable, and axialadjustment can only be accomplished by adjusting the stick-out of thecutting tool in the holder. It would be an advantage to provide a portcontour cutter which allows radial and axial adjustment in a simple andeffective manner.

SUMMARY OF THE INVENTION

Based upon the foregoing, the present invention provides a noveldrilling tool and method which overcomes limitations found in the priorart, and enables the efficient and effective production of port holes.It is therefore an object of the invention to provide a drilling toolcomprising a port contour cutter which allows machining of a port holeto produce the minor thread diameter and the port form in a singleoperation. In general, the drilling tool according to the inventioncomprises a tool holder having a rotational axis, with which drillinginserts are selectively mounted. A first drilling insert having cuttingsurfaces on a first side, and a mounting surface on a second sidethereof, is selectively mounted along the rotational axis of the toolholder. At least one second drilling insert having a predeterminedcutting surface portion and a mounting portion is selectively mountedwith the holder at a predetermined outboard location from the rotationalaxis of the holder. The at least one second drilling insert isnon-indexable. The invention also provides a method of drilling a porthole configuration to produce the minor thread diameter and the portform in a single operation.

These and other objects and advantages of the invention will becomeapparent upon a reading of the description of an embodiment thereof, inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a port hole configuration havinga connector coupled therewith, such as a hydraulic port seal connectionas found in the prior art.

FIG. 2 shows a side elevational view of an embodiment of the drillingtool according to the invention.

FIG. 3 shows a side elevation of the tool as shown in FIG. 2, rotated by90°.

FIG. 4 is a top view of the tool as shown in FIG. 2.

FIG. 5 is a partial exploded view showing the tool holder and drillinginserts according to an embodiment of the invention.

FIG. 6 is a side elevation view of a port form insert according to anembodiment of the invention.

FIG. 7 is a top view of the port form insert as shown in FIG. 6.

FIG. 8 is a side view of the port form insert as shown in FIG. 6.

FIG. 9 is a perspective view of the port form insert as shown in FIG. 6.

FIG. 10 is an elevational view of an alternate embodiment of theinvention.

FIG. 11 is a side elevation view of a port form insert according to anadditional embodiment of the invention.

FIG. 12 is a side elevational view of a drilling tool using the portform insert of FIG. 11 of an additional embodiment according to theinvention.

FIG. 13 is a top view of the embodiment of the drilling tool as shown inFIG. 12.

FIG. 14 is a side elevation of the tool as shown in FIG. 12, rotated by90.

DETAILED DESCRIPTION OF THE INVENTION

In one particular type of application, for a fluid port seal which isthreadably engaged with a hydraulic or other fluid line and sealed bymeans of an o-ring, requires a particular type of hole profile. As seenin FIG. 1, the shape of a fluid power port, such as a hydraulic porthole10, uses a truncated or tapered hole 12 leading into a threaded hole 14.A hydraulic connector to the porthole 16 is positioned above the porttaper 12 as shown at 18, and includes a flange 17 which bottoms outagainst the face of the work piece. Below the flange 17 are typicallystraight threads (not shown) formed on the connector, which engage thecylindrical, threaded hole at 14. To provide a seal for the connector16, an o-ring 20 is provided in association with an undercut 22 formedin the connector, which mates with the tapered portion of the hole 12,providing a seal seat for properly sealing the port. Different threadsmay be used in association with the connector 16, and the configurationof the machined tapered hole remains substantially consistent except forthe provision of alternative threading configurations. For example, inpractice, both imperial straight threads and metric straight threads maybe used with a hydraulic port, with other dimensions typically providedin metric dimensions. To identify a metric thread porthole, the portholemay be produced with an identification ridge 24, allowing simple andeffective identification that the port thread is metric.

Turning now to an embodiment of the present invention, FIGS. 2-4illustrate a drill tool assembly 50 for producing predeterminedconfiguration holes in a work piece. Drill tool assembly 50 comprises aholder 52, having a shank portion 54 and a head portion 56 associatedtherewith. Within the head portion 56, a mounting slot 58 is formed at acentral portion of the holder 52 to allow selective mounting of a firstdrilling insert 60 along the rotational axis of the holder 52. The slot58 may be configured to have a bottom wall positioned in substantiallyperpendicular orientation relative to the rotational axis of the holder52, and may include a locating boss or pin (not shown), positionedprecisely with respect to the rotational axis, for proper positioning ofinsert 60 along the rotational axis. The configuration of the toolholder 52 with respect to the mounting slot 58 may be generally similarto the tool holder and drill insert configuration such as produced byAllied Machine & Engineering Company, such as in the T-A™ drillingsystem. The drilling insert 60 is therefore precisely positioned withrespect to the holder 50, to perform the desired drilling function inconjunction therewith.

The holder 52 in this embodiment is shown to have a straight round shankleading to a ground qualified shoulder 55. The shank may be manufacturedwithout a locking flat to be usable with hydraulic chucks, heat shrinkholders or collet chucks, to gain higher dimensional accuracy,concentricity and balance. Alternatively a locking flat may be formed inthe holder 52. Alternative configurations of holder 52 are contemplated,such as with alternative shank configurations to adapt to a particularmachine spindle, such as CAT, BT, HSK, KM, ABS or the like. Precisionholders may have a qualified length to the face, which in turn requiresa ground shoulder on the cutting tool that is qualified, but again otherconfigurations are contemplated.

The insert 60 is securely mounted in association with head portion 56 bymeans of clamping arms 62 having apertures 63, which can accommodatescrews or other fasteners to secure the drill insert 60, havingcorresponding apertures 64. Each of the clamp arms 62 may also include acoolant or lubrication vent 66, which allows the application and flow ofa coolant or lubricant adjacent the cutting surfaces of the drill insert60, to facilitate the drilling operation. The vents 66 allow a liquid orair coolant/lubricant to be introduced to the hole bottom through thetool holder body 52. The liquid or air coolant helps to transportmachined cuttings from the hole bottom, as well as cool the drillinserts at and from the bottom of the machined hole. Alternatively, anexternal coolant supply may also be used if desired. The clamp arms 62may also include angled or curved surfaces 68, which facilitate chipremoval via chip evacuating grooves 70 on each side of the holder 52.

In the embodiment of the invention, there is also provided at least onesecond drill insert 80 coupled to the drill holder 52 at a predeterminedposition. In the embodiment as shown in the figures, at least one secondinsert 80 comprises a pair of such inserts mounted on opposing sides ofthe holder 52. The insert 80 includes a mounting aperture 82corresponding to a mounting aperture 84 formed in the holder 52. Theholder 52 is formed with insert seats 86, which precisely mount theinserts 80 in relation to the rotational axis of holder 52, in anon-indexable manner. This can be seen in FIG. 2, and similar to themounting configuration of insert 60, the mounting holes 82 formed ininserts 80 may be of tapered configuration, and slightly offset from theapertures 84 formed in the tool holder, to selectively bias the insertagainst the insert seat 86, for positive and precise mounting thereof.The connection of the inserts 60 and 80 and other aspects of the toolholder 52, may be generally similar to tool holder and insert mountingconfigurations as used in the Allied Machine & Engineering toolsmentioned previously, or such as described in co-owned U.S. Pat. No.5,957,635, which is hereby incorporated by reference herein. The inserts60 and 80 may be made of a sintered metallic hard material such ascarbide, cermet, ceramic, monocrystalline and polycrystalline diamond,or boron nitride as examples. Alternatively, high speed steel or othermaterials may be used.

The various inserts 60 and 80 in relation to the tool holder 52 areshown in FIG. 5. Using a single-sided inserts 60 and 80 in conjunctionwith tool holder 52, allows each of the inserts to be selectivelyremoved and replaced in a simple and effective manner upon wear of theinserts during a drilling operation. The drill insert 60 performs aprimary drilling operation, and may comprise the T-A™ drill insertproduced by the Allied Machine & Engineering Company. The drill insert60 in conjunction with tool holder 52, will produce the minor diameterfor the thread size required for production of a hydraulic port seal orother connection for fluid power ports, or for other possibleapplications. The depth for this minor diameter portion of the machinedwork piece is generally dictated by the port specification, but can alsobe changed to suit the application and produced as a special tool for adesired depth.

In the drilling tool 50, a port form portion comprises the at least onesecond insert 80, or as shown in this embodiment of the invention, twoopposing form inserts 80 mounted on tool holder 52. Using twoeffective/opposing form inserts 80 for the task of producing the portform in a machined work piece in conjunction with the minor diametermachine hole formed by insert 60, may enhance formation of both theminor thread diameter and port form in a single operation. In this way,the present invention provides a drilling system which does not requirepre-drilling, and will therefore save set up in production time as wellas tool cost associated with a pre-drilling operation. The replaceableinserts associated with the drilling system 50 will therefore notrequire braised carbide re-tipping or regrinding, which can result insize loss or the need to reset tool parameters. The use of preciselymachined inserts 60 and 80 allow repeatability in the machiningoperation, and allow the user to select drill speeds and feeds accordingto coated carbide or coated HSS drill recommendations as an example. Asthe machining operation of the minor thread diameter and port form isperformed at the same time, drill speeds can be set to the drilldiameter and not a spot faced diameter, as a spot face operationperformed by the insert 60 is of short duration and does not produceenough heat to damage the port form insert spot face area. By coatinginserts 60 and 80 with materials, such as titanium aluminum nitride(TiAlN), diamond or the like, the tool will have a longer life, andreplacement of the insert 60 and 80 is simple and efficient. It has alsobeen found that the combination of the drill insert 60 with the at leastone second insert 80 provides a drill system which is stabilized duringthe drilling operation, particularly when the port form inserts 80 areengaged in the work piece. Proper stabilization provides excellentsurface finish and accuracy in the machined work piece. The drillingtool system also allows the drilling operation to be performed withoutdwell, so that the spot face area cannot start scraping to producechatter or bad surface finish in the machined hole. In the drillingoperation, the holder 52 can be made to rotate a sufficient degree toclean up the spot face surface prior to retraction of the holder 52.

In the drilling system 50, the provision of a pair of second inserts 80allows the feed rate per insert to be the same as the feed rate perflute for the drill system 50, such that the feed rate per edge equalsthe feed rate per revolution divided by two. As shown in FIG. 5, theinsert seats 86 are located relative to the drill insert 60 mountinglocation in a predetermined manner. In the embodiment shown, the seat 86location is rotated approximately 15° below the drill insert 60location. This will enhance tool life of the drilling system 50 in thatchip flow coming from the drill insert 60 will not hit the port forminserts 80, which could cause possible damage to the cutting surfaces ofinserts 80. Further, the chip flow coming from the inserts 80 will notinterfere with the chip flow from the drill insert 60, ensuring goodchip evacuation from both inserts 60 and 80. In a preferred form, theangle of rotation, such as approximately 15°, is in-line with the axisof the tool, which opens the chip gullet and prevents clogging of thechips that could choke the drill system 50. Also, the rotation of theinserts may offset the multi-directional tool and cutting forces,decreasing harmonic vibrations and drill chatter. Although the rotationof the inserts 80 approximately 15° has been found to work effectively,the inserts may also be positioned without any rotation or at otherrotation angles, such as between 5°-25° for example.

Turning to FIGS. 6-9, an embodiment of the replaceable insert 80 isshown in more detail. As seen in these Figs., the insert 80 is generallyof rectangular plate form, allowing simple and cost effectivemanufacture of the inserts 80, along with simple and cost effectiveformation of the pockets or seating surfaces 86 in the holder 52. Theseaspects are similar for insert 60, wherein each of the insert 60 and 80allow precise repeatability of inserts having substantially identicalcharacteristics. The inserts 60 and 80 are also replaceable, andnon-indexable, to avoid problems of indexable inserts known in the priorart. For example, indexable inserts may have one side manufacturedwrong, making the entire insert scrap. Alternatively, after a first sideof an indexable insert is used, it can be easily mislocated or berendered unusable due to edge build up, chipped edges and/or brokenedges caused by the initial drilling operation. Providing simplymanufactured inserts 60 and 80, which are non-indexable, but easilyreplaceable, allows for a more cost effective operation than in the useof indexable inserts.

In the present invention, it may be desirable to hone a sharp edgeformed on the insert 80, which could result in chipping, such as by drybead blast honing or other suitable method. The hone may aid theadherence of a coating and prolonged tool life, as well as void chippingunder certain applications. At the same time, certain applications mayrequire a sharp edge, and such a sharp edge may be maintained in anun-honed and uncoated condition if desired. It may be desirable in anapplication in which honing is helpful, to provide a heavier hone at thespot facing edge and a lighter hone at the seal angle edge of the insert80, as will be hereinafter described. The degree of honing may becompatible with the actual chip thickness produced by the cuttingsurfaces of insert 80.

The insert 80 in general has a configuration which will be describedrelative to the minor diameter 90. At a top portion of the insert 80adjacent the minor diameter surface 90, a 45° chamfer 92 may beconfigured to lead into the seal angle cutting surface 94, whichtypically may be a 12-15° angled surface, but may be of another desiredangle. A chamfered surface 93 may be provided along the rear seatingsurface of the insert 80 to correspond to the seating surfaces machinedin the holder 52. The seal angle 94 terminates with a small cornerradius at 96 leading to the spot face 98. The spot face 98 depth fromthe top of the insert is predetermined based upon port specifications orthe like, and may be adapted for any particular application. At theoutside of the spot face 98, a small corner radius 100 leads to a secondangle 102 that shapes the outside wall of the spot face diameter at 104.The outside edge 104 of the insert 80 may be formed as a wiper edge thatproduces the inner diameter of the spot face, and may be configured tohave a slight angle between 0 and 5°, which will allow a slight amountof material to be shaved from the machined surface as the tool cutsdeeper so as to slightly enlarge the inner diameter and reduce burr inthe finished hole. Other angles for the wiper edge 104 are contemplated.

The insert 80 may be referred to as a “full form” insert, or a “wraparound” insert which desirably has the capability to cut around cornersand chamfers and blend all surfaces. In this way, a machined form isproduced without burrs, witness marks, sharp edges or other surfacedefects. In the embodiment as shown in FIG. 6-9, there is noted anoptional notch 106 which may be formed in the insert 80 to produce theidentification ridge 24 (as seen in FIG. 1), to identify the port asmetric.

In the manufacture of insert 80, by taking advantage of the port sealdiameter desired for a particular application, and the spot facediameter tolerances, a single port form may accommodate several portsizes. The inserts 80 can be made from blanks, such that a single blankmay accommodate more than one insert. The insert 80 may be coated byknown suitable methods, with a desired coating based upon a particularapplication for the tool 50. As an example, an application in aluminummay desirably use a diamond film coating on the inserts 60 and 80, orother coating materials, such as titanium aluminum nitride, may be used.

The inserts 80 generally may not need additional coolant holes, as thecutting action performed thereby is of relatively short duration, and atthe end of the drilling operation. Residual coolant from the hole beingdrilled, introduced by coolant holes 66 or an external coolant supply,may be sufficient for cooling the cutting surfaces of the inserts 80. Ifa through hole is provided, an outside source of coolant may berequired. Although the use of coolant holes to supply coolant directlyto the area of inserts 80 may not be necessary for certain applications,such additional coolant holes (shown in ghost at 67) could be providedif desired or needed for a particular application.

With the configuration of the inserts 80, several cutting surfaces areformed to produce desired machine surfaces in a work piece. The insert80 will have two different areas producing two different types ofmaterial chips, from the seal form surface 94 as well as spot facesurface 98. The seal form area cutting edge will enter the hole at anangle, such as between 12-15°, adjacent to the centerline. Due to thisacute angle, the theoretical chip thickness will only be approximately10-15% of the actual feed rate and the actual chip thickness notappreciably increased. In the spot face area, the cutting edge willapproach the material at approximately 90° to the centerline and thetheoretical chip thickness will be approximately 100%. In the embodimentshown in FIG. 2, as an example, the inserts 80 are placed above centerin the holder 52 to slightly increase the cutting pressures and reduceand/or eliminate chatter and vibration.

As an alternative embodiment, as shown in FIG. 10, and to provide radialand axial adjustment in the drilling system 50, the inserts 80 may belocated on an independent cartridge 110 formed to be mountable with theholder 52. A plurality of such cartridges 110 allowing radial and axialadjustment of the relative positions of inserts 80 relative to theholder 52 and cutting insert 60. Cartridges 110 may be nested againstthree sides for proper positioning relative to the holder and other toolcomponents, and fastened with a suitable fastener such as a screw. Inthis manner, the tool 50 may be fine tuned, even when mounted within aspindle for operation, in the case of spindle run-out or other problemsa turning machine may have. Adjustment of the cartridges may beperformed via shims, set screws or the like, to facilitaterepositioning.

An additional embodiment is shown in FIGS. 11 and 12 wherein the sideregister surfaces 90′ and 95′ of the insert 80′ are angled as shown byacute angles α and φ respectively. The modified insert 80′ is shownattached to angled seating surfaces 86′ of the holder 52′. It is alsocontemplated that only one of the side register surfaces 90′, 95′ isangled while the other remaining as in the embodiment shown in FIG. 6.Still another variation is shown in FIG. 14, wherein the side registersurfaces 90 and 95 of the insert 80 are positioned in seating surfacesthat are tilted as shown by acute angles α and φ respectively. Althoughnot shown, it is also contemplated that the seating surfaces 86 of theholder 52 and/or the side register surfaces 90, 95 of the insert 80 mayhave one or more locating ridges to properly position the insert 80within the holder.

An additional embodiment is shown in FIG. 13. In this embodiment theseating surfaces 86″ of the holder 52″ are asymmetrically positionedwith respect to the rotational axis of the holder 52″ such that thecircumferential distance represented by angle θ is less than one hundredeighty degrees. During operation, this varying distance between theinserts 80 causes the time between when the inserts engage the materialto vary during cutting. Varying the circumferential spacing between theinserts 80 helps eliminate harmonics during cutting. For embodimentswith three inserts, the angle between at least two sets of adjacentinserts would be other than one hundred twenty degrees and similarly formore inserts 80 and etc. for more inserts 80.

Although the present invention has been described above in detailrelative to a particular embodiment thereof, the same is by way ofillustration and example only, and is not to be taken as a limitation onthe present invention. Accordingly, the scope and content of the presentinvention are to be defined only by the terms of the appended claims.

1. A drilling tool comprising: a tool holder having a first end, asecond end, and an intermediate portion between the first end and thesecond end, and a rotational axis therethrough, the second endcomprising a shank portion, and the intermediate portion comprises atleast one insert attachment seat portion; at least one first drillingmember provided at the first end of the holder; at least one seconddrilling insert selectively attached to the at least one insert seatattachment portion of the intermediate portion of the holder, the seconddrilling insert comprising a first cutting edge generally parallel tothe rotational axis of the tool for forming the inner diameter of acounterbore, a second cutting edge generally perpendicular to the firstcutting edge for forming a bottom surface or spotface of thecounterbore, a third cutting edge formed transverse to the rotationalaxis of the cutting tool for forming a seal angle, and a fourth cuttingedge formed transverse to the rotational axis of the cutting tool forforming a chamfer, and the seat attachment portion having first, secondand third register surfaces that mate with corresponding register edgesand the back of the at least one second drilling insert; and wherein theat least one second insert is selectively replaceable and non-indexable.2. The drill tool of claim 1, wherein the at least one second drillinginsert is radially offset from the first drilling member.
 3. The drilltool of claim 2, wherein a line through the second cutting edge of theat least one second insert does not extend radially inward to therotational axis of the tool but rather is offset from the rotationalaxis of the tool.
 4. The drill tool of claim 1, wherein the at least onesecond insert is attached to bias the insert against the first, secondand third register surfaces.
 5. The drill tool of claim 1, wherein onthe at least one second insert a portion of the first cutting edge isslightly angled radially inward near the second cutting edge.
 6. Thedrill tool of claim 1, wherein the second cutting edge of the at leastone second insert includes a notch formed therein.
 7. The drill tool ofclaim 1, wherein the cutting edges of the at least one second insert arecoated.
 8. The drill tool of claim 1, wherein the first cutting edge ofthe at least one second insert has a second angle that shapes theoutside wall of the spot face diameter of a formed port seal hole. 9.The drill tool of claim 1, further comprising at least one coolant holeformed in the holder to direct coolant toward the cutting edges of theat least one second insert.
 10. The drill tool of claim 1, wherein saidat least one second insert is located on an independent cartridgeattachable to the intermediate portion of the holder, wherein aplurality of said cartridges are adapted to permit radial and axialadjustment of said at least one second insert position relative to saidholder.
 11. The drill tool of claim 1, wherein the at least one secondinsert is formed from a blank off material, wherein the thickness of theblank is substantially less than the width or length.
 12. A drillingtool comprising: a tool holder having a first end, a second end, and anintermediate portion between the first end and the second end and arotational axis therethrough, the first end comprising a holder slot,the second end comprising a shank portion, and the intermediate portioncomprising at least one insert attachment seat portion; at least onefirst drilling member being selectively attached within the holder slotof the first end of the holder; at least one secondary drilling insertattachable to the at least one insert attachment portion of theintermediate portion of the holder such that the at least one secondarydrilling insert comprises at least four cutting edges adapted to form aport seal; and wherein the at least one secondary insert is replaceableand non-indexable, and mates to first, second and third registersurfaces of the at least one insert attachment portion.
 13. The drilltool of claim 1, wherein the third register surface is parallel to orangled relative to the rotational axis.
 14. The drill tool of claim 1,wherein the first and second register surfaces are orthogonal or angledgreater than or less than 90° relative to one another.
 15. The drilltool of claim 12, wherein the third register surface is parallel to orangled relative to the rotational axis.
 16. The drill tool of claim 12,wherein the first and second register surfaces are orthogonal or angledgreater than or less than 90° relative to one another.
 17. A drillingtool comprising: a tool holder having a first end, a second end, and anintermediate portion between the first end and the second end, and arotational axis, the second end comprising a shank portion, and theintermediate portion comprises at least one insert attachment seatportion; a first cutting member selectively attached to the first end ofthe holder; and at least one drilling insert attachable to the at leastone insert seat attachment portion of the intermediate portion of theholder for forming a port seal in a single cutting operation, the atleast one insert comprising a first cutting edge for forming thediameter of counterbore, a second cutting edge for forming a bottomsurface or spotface of the counterbore, a third cutting edge for forminga seal angle, and a fourth cutting edge for forming a chamfer, whereinthe at least one drilling insert mates to first, second and thirdregister surfaces of the at least one insert attachment portion and isreplaceable and non-indexable.
 18. The drilling tool of claim 17,wherein the third register surface is parallel to or angled relative tothe rotational axis.
 19. The drilling tool of claim 17, wherein thefirst and second register surfaces are orthogonal or angled greater thanor less than 90° relative to one another.
 20. The drilling tool of claim1, wherein the a first cutting member is replaceable.